jsont

Simple json template language

Installation

$ npm install jsont

$ component install CamShaft/jsont

Features

• Simple
• Valid JSON
• Extensible
• Auto-parallelization of templated properties

Example

Input:

{
  "name": "`user.firstName`",
  "birthday": "`user.birthday | date:'MMMM Do'`",
  "addresses": "`user.addresses | map | partial:address`"
}

Output:

{
  "name": "Cameron",
  "birthday": "September 19th",
  "addresses": [
    {
      "street": "123 Fake Street",
      "city": "Nowhere",
      "country": "USA"
    },
    {
      "street": "Broadway Street",
      "city": "NY",
      "country": "USA"
    }
  ]
}

Usage

var jsont = require('jsont')();

var template = require('./my-template.json');

var options = {};

jsont.render(template, options, function(err, out) {
  console.log(out);
});

Helpers

You can easily extend jsont by calling use:

var jsont = require('jsont')();

jsont.use('reverse', function(input, next) {
  next(null, input.split("").reverse().join(""));
});

In your template you can then call the helper by piping data to it:

{
  "reversed-name": "'Cameron' | reverse"
}

Out comes:

{
  "reversed-name": "noremaC"
}

You can also pass arguments and chain helpers

{
  "list": "'1,2,3,4,5' | split:',' | map | to-int"
}

jsont.use('split', function(input, separator, next) {
  next(null, input.split(separator));
});

jsont.use('to-int', function(input, next) {
  next(null, parseInt(input));
});

And we get:

{
  "list": [
    1,
    2,
    3,
    4,
    5
  ]
}

Parallelization

Since helpers are all asynchronous behind the scenes we get parallelization in a simple form:

var api = require('./api');

jsont.use('user-likes', function(user, next) {
  if (typeof user !== 'object') user = {id: user};

  api.likes(user.id, function(err, likes) {
    if (err) return next(err);

    user.likes = likes;
    next(null, user);
  });
});

jsont.use('user-followers', function(id, next) {
  api.followers(id, next);
});

jsont.use('user', function(id, next) {
  api.get(id, function(err, user) {
    if (err) return next(err);

    user.id = id;
    next(null, user);
  });
});

jsont.use('length', function(user, property, position, next) {
  if (typeof position === 'function') return position(null, user[property].length);
  user[position] = user[property].length;
  next(null, user);
});

jsont.renderFile('user-profile.json', {id: 0}, function(err, out) {
  console.log(out);
});

{
  "id": "`id`",
  "likes": "`id | user-likes | length:likes`",
  "followers": "`id | user-followers | map | user | user-likes | length:likes,likes`"
}

Everything gets put on the event loop and renders as responses come back.

{
  "id": "1",
  "likes": 4,
  "followers": [
    {
      "id": "2",
      "name": "Scott",
      "likes": 3
    },
    {
      "id": "3",
      "name": "Dave",
      "likes": 2
    }
  ]
}

Tests

$ npm test

TODO

• Create a richer evaluator to do something like:

  {
    "user": "`{id: id, name: name} | my-helper`"
  }

• Cache compiled templates using the filename option

• Expose concurrency settings

• Allow option to configure escape character